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From: Martin Schwidefsky <schwidefsky@de.ibm.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org,
	David Hildenbrand <david@redhat.com>,
	Cornelia Huck <cohuck@redhat.com>
Subject: Re: [PATCH 4.4 15/50] s390/alternative: use a copy of the facility bit mask
Date: Mon, 7 May 2018 08:07:07 +0200	[thread overview]
Message-ID: <20180507080707.2a41ae28@mschwideX1> (raw)
In-Reply-To: <20180504221808.GB24813@kroah.com>

On Fri, 4 May 2018 15:18:08 -0700
Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:

> On Fri, May 04, 2018 at 09:37:20AM +0200, Jiri Slaby wrote:
> > On 04/27/2018, 03:58 PM, Greg Kroah-Hartman wrote:  
> > > 4.4-stable review patch.  If anyone has any objections, please let me know.
> > > 
> > > ------------------
> > > 
> > > From: Martin Schwidefsky <schwidefsky@de.ibm.com>
> > > 
> > > 
> > > [ Upstream commit cf1489984641369611556bf00c48f945c77bcf02 ]
> > > 
> > > To be able to switch off specific CPU alternatives with kernel parameters
> > > make a copy of the facility bit mask provided by STFLE and use the copy
> > > for the decision to apply an alternative.  
> > ...  
> > > --- a/arch/s390/include/asm/facility.h
> > > +++ b/arch/s390/include/asm/facility.h
> > > @@ -13,6 +13,24 @@
> > >  
> > >  #define MAX_FACILITY_BIT (256*8)	/* stfle_fac_list has 256 bytes */  
> > 
> > I wonder if the below (plus __test_facility) is correct in 4.4, given
> > MAX_FACILITY_BIT is defined as such and not as sizeof(stfle_fac_list *
> > 8) as in upstream?  
> 
> I'm going to defer to Marin here, as he did the backport...
> Martin?

Good catch. With MAX_FACILITY_BIT == 2048 and the patch applied the result
for a test_facility/__test_facility call with a facility number >= 1024
would give an incorrect result. Fortunately there are no such calls in
the current 4.4 kernel source. And there are no facilities defined with
bit numbers this large, so even out-of-tree code would not do this if
it is sane.

To correct this the MAX_FACILITY_BIT define needs to be reduced to 1024
which would require the patch pointed out be Heiko:

commit 6f5165e864d240d15675cc2fb5a369d57e1f60d0
Author: Heiko Carstens <heiko.carstens@de.ibm.com>
Date:   Mon Mar 20 14:29:50 2017 +0100

    s390/facilites: use stfle_fac_list array size for MAX_FACILITY_BIT

I would say yes, it *does* make sense to include this patch even if it
does not fix anything.

-- 
blue skies,
   Martin.

"Reality continues to ruin my life." - Calvin.

  reply	other threads:[~2018-05-07  6:07 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-27 13:58 [PATCH 4.4 00/50] 4.4.130-stable review Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 01/50] cifs: do not allow creating sockets except with SMB1 posix exensions Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 02/50] x86/tsc: Prevent 32bit truncation in calc_hpet_ref() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 03/50] perf: Return proper values for user stack errors Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 04/50] staging: ion : Donnot wakeup kswapd in ion system alloc Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 05/50] r8152: add Linksys USB3GIGV1 id Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 06/50] Input: drv260x - fix initializing overdrive voltage Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 07/50] ath9k_hw: check if the chip failed to wake up Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 08/50] jbd2: fix use after free in kjournald2() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 09/50] Revert "ath10k: send (re)assoc peer command when NSS changed" Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 10/50] s390: introduce CPU alternatives Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 11/50] s390: enable CPU alternatives unconditionally Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 12/50] KVM: s390: wire up bpb feature Greg Kroah-Hartman
2018-04-27 15:10   ` Christian Borntraeger
2018-04-27 15:17     ` Greg Kroah-Hartman
2018-04-27 15:46       ` Greg Kroah-Hartman
2018-04-27 15:53         ` Christian Borntraeger
2018-04-29  7:51           ` Martin Schwidefsky
2018-04-30 18:17             ` Greg Kroah-Hartman
2018-04-30 18:30               ` Christian Borntraeger
2018-04-27 13:58 ` [PATCH 4.4 13/50] s390: scrub registers on kernel entry and KVM exit Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 14/50] s390: add optimized array_index_mask_nospec Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 15/50] s390/alternative: use a copy of the facility bit mask Greg Kroah-Hartman
2018-05-04  7:37   ` Jiri Slaby
2018-05-04  7:41     ` Jiri Slaby
2018-05-04 22:18     ` Greg Kroah-Hartman
2018-05-07  6:07       ` Martin Schwidefsky [this message]
2018-05-08  7:20         ` Greg Kroah-Hartman
2018-05-12 19:44           ` Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 16/50] s390: add options to change branch prediction behaviour for the kernel Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 17/50] s390: run user space and KVM guests with modified branch prediction Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 18/50] s390: introduce execute-trampolines for branches Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 19/50] s390: Replace IS_ENABLED(EXPOLINE_*) with IS_ENABLED(CONFIG_EXPOLINE_*) Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 20/50] s390: do not bypass BPENTER for interrupt system calls Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 21/50] s390/entry.S: fix spurious zeroing of r0 Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 22/50] s390: move nobp parameter functions to nospec-branch.c Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 23/50] s390: add automatic detection of the spectre defense Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 24/50] s390: report spectre mitigation via syslog Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 25/50] s390: add sysfs attributes for spectre Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 26/50] s390: correct nospec auto detection init order Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 27/50] s390: correct module section names for expoline code revert Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 28/50] bonding: do not set slave_dev npinfo before slave_enable_netpoll in bond_enslave Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 29/50] KEYS: DNS: limit the length of option strings Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 30/50] l2tp: check sockaddr length in pppol2tp_connect() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 31/50] net: validate attribute sizes in neigh_dump_table() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 32/50] llc: delete timers synchronously in llc_sk_free() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 33/50] tcp: dont read out-of-bounds opsize Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 34/50] team: avoid adding twice the same option to the event list Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 35/50] team: fix netconsole setup over team Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 36/50] packet: fix bitfield update race Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 37/50] pppoe: check sockaddr length in pppoe_connect() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 38/50] vlan: Fix reading memory beyond skb->tail in skb_vlan_tagged_multi Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 39/50] sctp: do not check port in sctp_inet6_cmp_addr Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 40/50] llc: hold llc_sap before release_sock() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 41/50] llc: fix NULL pointer deref for SOCK_ZAPPED Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 42/50] tipc: add policy for TIPC_NLA_NET_ADDR Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 43/50] net: fix deadlock while clearing neighbor proxy table Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 44/50] tcp: md5: reject TCP_MD5SIG or TCP_MD5SIG_EXT on established sockets Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 45/50] net: af_packet: fix race in PACKET_{R|T}X_RING Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 46/50] ipv6: add RTA_TABLE and RTA_PREFSRC to rtm_ipv6_policy Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 47/50] scsi: mptsas: Disable WRITE SAME Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 48/50] cdrom: information leak in cdrom_ioctl_media_changed() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 49/50] s390/cio: update chpid descriptor after resource accessibility event Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 50/50] s390/uprobes: implement arch_uretprobe_is_alive() Greg Kroah-Hartman
2018-04-27 18:15 ` [PATCH 4.4 00/50] 4.4.130-stable review Shuah Khan
2018-04-27 18:57 ` Nathan Chancellor
2018-04-27 19:43 ` kernelci.org bot
2018-04-27 20:31 ` Dan Rue
2018-04-28 14:25 ` Guenter Roeck

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